diff --git a/asm/non_matching/m4a/CgbSound.inc b/asm/non_matching/m4a/CgbSound.inc
deleted file mode 100644
index c4fadc4d..00000000
--- a/asm/non_matching/m4a/CgbSound.inc
+++ /dev/null
@@ -1,616 +0,0 @@
-
-    .syntax unified
-
-    .text
-
-	push {r4, r5, r6, r7, lr}
-	mov r7, sl
-	mov r6, sb
-	mov r5, r8
-	push {r5, r6, r7}
-	sub sp, #0x24
-	ldr r0, _080B0B74 @ =0x03007FF0
-	ldr r0, [r0]
-	str r0, [sp, #8]
-	ldrb r0, [r0, #0xa]
-	cmp r0, #0
-	beq _080B0B78
-	subs r0, #1
-	ldr r1, [sp, #8]
-	strb r0, [r1, #0xa]
-	b _080B0B7E
-	.align 2, 0
-_080B0B74: .4byte 0x03007FF0
-_080B0B78:
-	movs r0, #0xe
-	ldr r3, [sp, #8]
-	strb r0, [r3, #0xa]
-_080B0B7E:
-	movs r6, #1
-	ldr r0, [sp, #8]
-	ldr r4, [r0, #0x1c]
-	mov r1, sp
-	str r1, [sp, #0x1c]
-_080B0B88:
-	ldrb r1, [r4]
-	movs r0, #0xc7
-	ands r0, r1
-	adds r3, r6, #1
-	mov sl, r3
-	movs r1, #0x40
-	adds r1, r1, r4
-	mov sb, r1
-	cmp r0, #0
-	bne _080B0B9E
-	b _080B0FBA
-_080B0B9E:
-	cmp r6, #2
-	beq _080B0BD4
-	cmp r6, #2
-	bgt _080B0BAC
-	cmp r6, #1
-	beq _080B0BB2
-	b _080B0C1C
-_080B0BAC:
-	cmp r6, #3
-	beq _080B0BF8
-	b _080B0C1C
-_080B0BB2:
-	ldr r3, _080B0BC8 @ =0x04000060
-	str r3, [sp, #0xc]
-	adds r3, #2
-	ldr r0, _080B0BCC @ =0x04000063
-	str r0, [sp, #0x10]
-	ldr r1, _080B0BD0 @ =0x04000064
-	str r1, [sp, #0x14]
-	adds r0, #2
-	str r0, [sp, #0x18]
-	movs r0, #0
-	b _080B0C30
-	.align 2, 0
-_080B0BC8: .4byte 0x04000060
-_080B0BCC: .4byte 0x04000063
-_080B0BD0: .4byte 0x04000064
-_080B0BD4:
-	ldr r3, _080B0BEC @ =0x04000061
-	str r3, [sp, #0xc]
-	adds r3, #7
-	ldr r0, _080B0BF0 @ =0x04000069
-	str r0, [sp, #0x10]
-	ldr r1, _080B0BF4 @ =0x0400006C
-	str r1, [sp, #0x14]
-	adds r0, #4
-	str r0, [sp, #0x18]
-	movs r0, #1
-	b _080B0C30
-	.align 2, 0
-_080B0BEC: .4byte 0x04000061
-_080B0BF0: .4byte 0x04000069
-_080B0BF4: .4byte 0x0400006C
-_080B0BF8:
-	ldr r3, _080B0C10 @ =0x04000070
-	str r3, [sp, #0xc]
-	adds r3, #2
-	ldr r0, _080B0C14 @ =0x04000073
-	str r0, [sp, #0x10]
-	ldr r1, _080B0C18 @ =0x04000074
-	str r1, [sp, #0x14]
-	adds r0, #2
-	str r0, [sp, #0x18]
-	movs r0, #2
-	b _080B0C30
-	.align 2, 0
-_080B0C10: .4byte 0x04000070
-_080B0C14: .4byte 0x04000073
-_080B0C18: .4byte 0x04000074
-_080B0C1C:
-	ldr r3, _080B0C84 @ =0x04000071
-	str r3, [sp, #0xc]
-	adds r3, #7
-	ldr r0, _080B0C88 @ =0x04000079
-	str r0, [sp, #0x10]
-	ldr r1, _080B0C8C @ =0x0400007C
-	str r1, [sp, #0x14]
-	adds r0, #4
-	str r0, [sp, #0x18]
-	movs r0, #3
-_080B0C30:
-	ldr r1, [sp, #0x1c]
-	strb r0, [r1]
-	ldr r0, [sp, #8]
-	ldrb r0, [r0, #0xa]
-	str r0, [sp, #4]
-	ldr r1, [sp, #0x10]
-	ldrb r0, [r1]
-	mov r8, r0
-	ldrb r2, [r4]
-	movs r0, #0x80
-	ands r0, r2
-	cmp r0, #0
-	beq _080B0D2A
-	movs r7, #0x40
-	adds r0, r7, #0
-	ands r0, r2
-	lsls r0, r0, #0x18
-	lsrs r5, r0, #0x18
-	adds r0, r6, #1
-	mov sl, r0
-	movs r1, #0x40
-	adds r1, r1, r4
-	mov sb, r1
-	cmp r5, #0
-	beq _080B0C64
-	b _080B0D60
-_080B0C64:
-	movs r0, #3
-	strb r0, [r4]
-	strb r0, [r4, #0x1d]
-	adds r0, r4, #0
-	str r3, [sp, #0x20]
-	bl CgbModVol
-	ldr r3, [sp, #0x20]
-	cmp r6, #2
-	beq _080B0C9C
-	cmp r6, #2
-	bgt _080B0C90
-	cmp r6, #1
-	beq _080B0C96
-	b _080B0CF0
-	.align 2, 0
-_080B0C84: .4byte 0x04000071
-_080B0C88: .4byte 0x04000079
-_080B0C8C: .4byte 0x0400007C
-_080B0C90:
-	cmp r6, #3
-	beq _080B0CA8
-	b _080B0CF0
-_080B0C96:
-	ldrb r0, [r4, #0x1f]
-	ldr r1, [sp, #0xc]
-	strb r0, [r1]
-_080B0C9C:
-	ldr r0, [r4, #0x24]
-	lsls r0, r0, #6
-	ldrb r1, [r4, #0x1e]
-	adds r0, r0, r1
-	strb r0, [r3]
-	b _080B0CFC
-_080B0CA8:
-	ldr r1, [r4, #0x24]
-	ldr r0, [r4, #0x28]
-	cmp r1, r0
-	beq _080B0CD0
-	ldr r0, [sp, #0xc]
-	strb r7, [r0]
-	ldr r1, _080B0CE4 @ =0x04000090
-	ldr r2, [r4, #0x24]
-	ldr r0, [r2]
-	str r0, [r1]
-	adds r1, #4
-	ldr r0, [r2, #4]
-	str r0, [r1]
-	adds r1, #4
-	ldr r0, [r2, #8]
-	str r0, [r1]
-	adds r1, #4
-	ldr r0, [r2, #0xc]
-	str r0, [r1]
-	str r2, [r4, #0x28]
-_080B0CD0:
-	ldr r1, [sp, #0xc]
-	strb r5, [r1]
-	ldrb r0, [r4, #0x1e]
-	strb r0, [r3]
-	ldrb r0, [r4, #0x1e]
-	cmp r0, #0
-	beq _080B0CE8
-	movs r0, #0xc0
-	b _080B0D0A
-	.align 2, 0
-_080B0CE4: .4byte 0x04000090
-_080B0CE8:
-	movs r3, #0x80
-	rsbs r3, r3, #0
-	strb r3, [r4, #0x1a]
-	b _080B0D0C
-_080B0CF0:
-	ldrb r0, [r4, #0x1e]
-	strb r0, [r3]
-	ldr r0, [r4, #0x24]
-	lsls r0, r0, #3
-	ldr r1, [sp, #0x14]
-	strb r0, [r1]
-_080B0CFC:
-	ldrb r0, [r4, #4]
-	adds r0, #8
-	mov r8, r0
-	ldrb r0, [r4, #0x1e]
-	cmp r0, #0
-	beq _080B0D0A
-	movs r0, #0x40
-_080B0D0A:
-	strb r0, [r4, #0x1a]
-_080B0D0C:
-	ldrb r1, [r4, #4]
-	movs r2, #0
-	strb r1, [r4, #0xb]
-	movs r0, #0xff
-	ands r0, r1
-	adds r3, r6, #1
-	mov sl, r3
-	movs r1, #0x40
-	adds r1, r1, r4
-	mov sb, r1
-	cmp r0, #0
-	bne _080B0D26
-	b _080B0E7A
-_080B0D26:
-	strb r2, [r4, #9]
-	b _080B0EA8
-_080B0D2A:
-	movs r0, #4
-	ands r0, r2
-	cmp r0, #0
-	bne _080B0D44
-	ldr r0, _080B0D70 @ =0x04000084
-	ldrb r1, [r0]
-	ldr r3, [sp, #0x1c]
-	ldrb r0, [r3]
-	asrs r1, r0
-	movs r0, #1
-	ands r1, r0
-	cmp r1, #0
-	bne _080B0D74
-_080B0D44:
-	ldrb r0, [r4, #0xd]
-	subs r0, #1
-	strb r0, [r4, #0xd]
-	movs r1, #0xff
-	ands r0, r1
-	lsls r0, r0, #0x18
-	adds r3, r6, #1
-	mov sl, r3
-	movs r1, #0x40
-	adds r1, r1, r4
-	mov sb, r1
-	cmp r0, #0
-	ble _080B0D60
-	b _080B0EBA
-_080B0D60:
-	lsls r0, r6, #0x18
-	lsrs r0, r0, #0x18
-	bl CgbOscOff
-	movs r0, #0
-	strb r0, [r4]
-	b _080B0FB6
-	.align 2, 0
-_080B0D70: .4byte 0x04000084
-_080B0D74:
-	movs r0, #0x40
-	ands r0, r2
-	adds r3, r6, #1
-	mov sl, r3
-	movs r1, #0x40
-	adds r1, r1, r4
-	mov sb, r1
-	cmp r0, #0
-	beq _080B0DB4
-	movs r0, #3
-	ands r0, r2
-	cmp r0, #0
-	beq _080B0DB4
-	movs r0, #0xfc
-	ands r0, r2
-	movs r2, #0
-	strb r0, [r4]
-	ldrb r1, [r4, #7]
-	strb r1, [r4, #0xb]
-	movs r0, #0xff
-	ands r0, r1
-	cmp r0, #0
-	beq _080B0DE6
-	ldrb r0, [r4, #0x1d]
-	movs r1, #1
-	orrs r0, r1
-	strb r0, [r4, #0x1d]
-	cmp r6, #3
-	beq _080B0EA8
-	ldrb r3, [r4, #7]
-	mov r8, r3
-	b _080B0EA8
-_080B0DB4:
-	ldrb r0, [r4, #0xb]
-	cmp r0, #0
-	bne _080B0EA8
-	cmp r6, #3
-	bne _080B0DC6
-	ldrb r1, [r4, #0x1d]
-	movs r0, #1
-	orrs r0, r1
-	strb r0, [r4, #0x1d]
-_080B0DC6:
-	adds r0, r4, #0
-	bl CgbModVol
-	ldrb r0, [r4]
-	movs r1, #3
-	ands r1, r0
-	cmp r1, #0
-	bne _080B0E18
-	ldrb r0, [r4, #9]
-	subs r0, #1
-	strb r0, [r4, #9]
-	movs r1, #0xff
-	ands r0, r1
-	lsls r0, r0, #0x18
-	cmp r0, #0
-	bgt _080B0E14
-_080B0DE6:
-	ldrb r1, [r4, #0xa]
-	ldrb r0, [r4, #0xc]
-	muls r0, r1, r0
-	adds r0, #0xff
-	asrs r0, r0, #8
-	movs r1, #0
-	strb r0, [r4, #9]
-	lsls r0, r0, #0x18
-	cmp r0, #0
-	beq _080B0D60
-	ldrb r0, [r4]
-	movs r1, #4
-	orrs r0, r1
-	strb r0, [r4]
-	ldrb r0, [r4, #0x1d]
-	movs r1, #1
-	orrs r0, r1
-	strb r0, [r4, #0x1d]
-	cmp r6, #3
-	beq _080B0EBA
-	movs r3, #8
-	mov r8, r3
-	b _080B0EBA
-_080B0E14:
-	ldrb r0, [r4, #7]
-	b _080B0EA6
-_080B0E18:
-	cmp r1, #1
-	bne _080B0E24
-_080B0E1C:
-	ldrb r0, [r4, #0x19]
-	strb r0, [r4, #9]
-	movs r0, #7
-	b _080B0EA6
-_080B0E24:
-	cmp r1, #2
-	bne _080B0E6A
-	ldrb r0, [r4, #9]
-	subs r0, #1
-	strb r0, [r4, #9]
-	movs r1, #0xff
-	ands r0, r1
-	lsls r0, r0, #0x18
-	asrs r0, r0, #0x18
-	movs r1, #0x19
-	ldrsb r1, [r4, r1]
-	cmp r0, r1
-	bgt _080B0E66
-_080B0E3E:
-	ldrb r0, [r4, #6]
-	cmp r0, #0
-	bne _080B0E4E
-	ldrb r1, [r4]
-	movs r0, #0xfc
-	ands r0, r1
-	strb r0, [r4]
-	b _080B0DE6
-_080B0E4E:
-	ldrb r0, [r4]
-	subs r0, #1
-	strb r0, [r4]
-	ldrb r1, [r4, #0x1d]
-	movs r0, #1
-	orrs r0, r1
-	strb r0, [r4, #0x1d]
-	cmp r6, #3
-	beq _080B0E1C
-	movs r3, #8
-	mov r8, r3
-	b _080B0E1C
-_080B0E66:
-	ldrb r0, [r4, #5]
-	b _080B0EA6
-_080B0E6A:
-	ldrb r0, [r4, #9]
-	adds r0, #1
-	strb r0, [r4, #9]
-	movs r1, #0xff
-	ands r0, r1
-	ldrb r3, [r4, #0xa]
-	cmp r0, r3
-	blo _080B0EA4
-_080B0E7A:
-	ldrb r0, [r4]
-	subs r0, #1
-	movs r2, #0
-	strb r0, [r4]
-	ldrb r1, [r4, #5]
-	strb r1, [r4, #0xb]
-	movs r0, #0xff
-	ands r0, r1
-	cmp r0, #0
-	beq _080B0E3E
-	ldrb r0, [r4, #0x1d]
-	movs r1, #1
-	orrs r0, r1
-	strb r0, [r4, #0x1d]
-	ldrb r0, [r4, #0xa]
-	strb r0, [r4, #9]
-	cmp r6, #3
-	beq _080B0EA8
-	ldrb r0, [r4, #5]
-	mov r8, r0
-	b _080B0EA8
-_080B0EA4:
-	ldrb r0, [r4, #4]
-_080B0EA6:
-	strb r0, [r4, #0xb]
-_080B0EA8:
-	ldrb r0, [r4, #0xb]
-	subs r0, #1
-	strb r0, [r4, #0xb]
-	ldr r1, [sp, #4]
-	cmp r1, #0
-	bne _080B0EBA
-	subs r1, #1
-	str r1, [sp, #4]
-	b _080B0DB4
-_080B0EBA:
-	ldrb r1, [r4, #0x1d]
-	movs r0, #2
-	ands r0, r1
-	cmp r0, #0
-	beq _080B0F34
-	cmp r6, #3
-	bgt _080B0EFA
-	ldrb r1, [r4, #1]
-	movs r0, #8
-	ands r0, r1
-	cmp r0, #0
-	beq _080B0EFA
-	ldr r0, _080B0EE4 @ =0x04000089
-	ldrb r0, [r0]
-	adds r1, r0, #0
-	cmp r1, #0x3f
-	bgt _080B0EEC
-	ldr r0, [r4, #0x20]
-	adds r0, #2
-	ldr r1, _080B0EE8 @ =0x000007FC
-	b _080B0EF6
-	.align 2, 0
-_080B0EE4: .4byte 0x04000089
-_080B0EE8: .4byte 0x000007FC
-_080B0EEC:
-	cmp r1, #0x7f
-	bgt _080B0EFA
-	ldr r0, [r4, #0x20]
-	adds r0, #1
-	ldr r1, _080B0F04 @ =0x000007FE
-_080B0EF6:
-	ands r0, r1
-	str r0, [r4, #0x20]
-_080B0EFA:
-	cmp r6, #4
-	beq _080B0F08
-	ldr r0, [r4, #0x20]
-	b _080B0F14
-	.align 2, 0
-_080B0F04: .4byte 0x000007FE
-_080B0F08:
-	ldr r1, [sp, #0x14]
-	ldrb r0, [r1]
-	movs r1, #8
-	ands r1, r0
-	ldr r0, [r4, #0x20]
-	orrs r0, r1
-_080B0F14:
-	ldr r3, [sp, #0x14]
-	strb r0, [r3]
-	ldrb r0, [r4, #0x1a]
-	movs r1, #0xc0
-	ands r1, r0
-	ldr r0, [r4, #0x20]
-	movs r2, #0xfc
-	lsls r2, r2, #6
-	ands r0, r2
-	lsrs r0, r0, #8
-	adds r1, r1, r0
-	strb r1, [r4, #0x1a]
-	movs r0, #0xff
-	ands r1, r0
-	ldr r3, [sp, #0x18]
-	strb r1, [r3]
-_080B0F34:
-	ldrb r1, [r4, #0x1d]
-	movs r0, #1
-	ands r0, r1
-	cmp r0, #0
-	beq _080B0FB6
-	ldr r2, _080B0F7C @ =0x04000081
-	ldrb r1, [r4, #0x1c]
-	ldrb r0, [r2]
-	bics r0, r1
-	ldrb r1, [r4, #0x1b]
-	orrs r0, r1
-	strb r0, [r2]
-	cmp r6, #3
-	bne _080B0F84
-	ldr r1, _080B0F80 @ =gCgb3Vol
-	ldrb r0, [r4, #9]
-	adds r0, r0, r1
-	ldrb r0, [r0]
-	ldr r1, [sp, #0x10]
-	strb r0, [r1]
-	ldrb r1, [r4, #0x1a]
-	movs r2, #0x80
-	adds r0, r2, #0
-	ands r0, r1
-	cmp r0, #0
-	beq _080B0FB6
-	ldr r3, [sp, #0xc]
-	strb r2, [r3]
-	ldrb r0, [r4, #0x1a]
-	ldr r1, [sp, #0x18]
-	strb r0, [r1]
-	ldrb r1, [r4, #0x1a]
-	movs r0, #0x7f
-	ands r0, r1
-	strb r0, [r4, #0x1a]
-	b _080B0FB6
-	.align 2, 0
-_080B0F7C: .4byte 0x04000081
-_080B0F80: .4byte gCgb3Vol
-_080B0F84:
-	movs r0, #0xf
-	mov r3, r8
-	ands r3, r0
-	mov r8, r3
-	ldrb r0, [r4, #9]
-	lsls r0, r0, #4
-	add r0, r8
-	ldr r1, [sp, #0x10]
-	strb r0, [r1]
-	ldrb r0, [r4, #0x1a]
-	movs r2, #0x80
-	orrs r0, r2
-	ldr r3, [sp, #0x18]
-	strb r0, [r3]
-	cmp r6, #1
-	bne _080B0FB6
-	ldr r0, [sp, #0xc]
-	ldrb r1, [r0]
-	movs r0, #8
-	ands r0, r1
-	cmp r0, #0
-	bne _080B0FB6
-	ldrb r0, [r4, #0x1a]
-	orrs r0, r2
-	strb r0, [r3]
-_080B0FB6:
-	movs r0, #0
-	strb r0, [r4, #0x1d]
-_080B0FBA:
-	mov r6, sl
-	mov r4, sb
-	cmp r6, #4
-	bgt _080B0FC4
-	b _080B0B88
-_080B0FC4:
-	add sp, #0x24
-	pop {r3, r4, r5}
-	mov r8, r3
-	mov sb, r4
-	mov sl, r5
-	pop {r4, r5, r6, r7}
-	pop {r0}
-	bx r0
-
-    .syntax divided
diff --git a/src/gba/m4a.c b/src/gba/m4a.c
index 19978368..b5e2e13e 100644
--- a/src/gba/m4a.c
+++ b/src/gba/m4a.c
@@ -1059,16 +1059,9 @@ void CgbModVol(CgbChannel* chan) {
 
     if (!CgbPan(chan)) {
         chan->pan = 0xFF;
-        chan->envelopeGoal = (u32)(chan->rightVolume + chan->leftVolume) >> 4;
+        chan->envelopeGoal = (u32)(chan->rightVolume + chan->leftVolume) / 16;
     } else {
-        // Force chan->rightVolume and chan->leftVolume to be read from memory again,
-        // even though there is no reason to do so.
-        // The command line option "-fno-gcse" achieves the same result as this.
-#ifndef NON_MATCHING
-        asm("" : : : "memory");
-#endif
-
-        chan->envelopeGoal = (u32)(chan->rightVolume + chan->leftVolume) >> 4;
+        chan->envelopeGoal = (u32)(chan->rightVolume + chan->leftVolume) / 16;
         if (chan->envelopeGoal > 15)
             chan->envelopeGoal = 15;
     }
@@ -1077,7 +1070,7 @@ void CgbModVol(CgbChannel* chan) {
     chan->pan &= chan->panMask;
 }
 
-NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
+void CgbSound(void) {
     s32 ch;
     CgbChannel* channels;
     s32 envelopeStepTimeAndDir;
@@ -1088,6 +1081,8 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
     vu8* nrx2ptr;
     vu8* nrx3ptr;
     vu8* nrx4ptr;
+    vu8* sp1C;
+    u8 sp00;
 
     // Most comparision operations that cast to s8 perform 'and' by 0xFF.
     int mask = 0xff;
@@ -1097,7 +1092,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
     else
         soundInfo->c15 = 14;
 
-    for (ch = 1, channels = soundInfo->cgbChannels; ch <= 4; ch++, channels++) {
+    for (ch = 1, channels = soundInfo->cgbChannels, sp1C = &sp00; ch <= 4; ch++, channels++) {
         if (!(channels->statusFlags & SOUND_CHANNEL_SF_ON))
             continue;
 
@@ -1109,6 +1104,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
                 nrx2ptr = (vu8*)(REG_ADDR_NR12);
                 nrx3ptr = (vu8*)(REG_ADDR_NR13);
                 nrx4ptr = (vu8*)(REG_ADDR_NR14);
+                *sp1C = 0;
                 break;
             case 2:
                 nrx0ptr = (vu8*)(REG_ADDR_NR10 + 1);
@@ -1116,6 +1112,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
                 nrx2ptr = (vu8*)(REG_ADDR_NR22);
                 nrx3ptr = (vu8*)(REG_ADDR_NR23);
                 nrx4ptr = (vu8*)(REG_ADDR_NR24);
+                *sp1C = 1;
                 break;
             case 3:
                 nrx0ptr = (vu8*)(REG_ADDR_NR30);
@@ -1123,6 +1120,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
                 nrx2ptr = (vu8*)(REG_ADDR_NR32);
                 nrx3ptr = (vu8*)(REG_ADDR_NR33);
                 nrx4ptr = (vu8*)(REG_ADDR_NR34);
+                *sp1C = 2;
                 break;
             default:
                 nrx0ptr = (vu8*)(REG_ADDR_NR30 + 1);
@@ -1130,6 +1128,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
                 nrx2ptr = (vu8*)(REG_ADDR_NR42);
                 nrx3ptr = (vu8*)(REG_ADDR_NR43);
                 nrx4ptr = (vu8*)(REG_ADDR_NR44);
+                *sp1C = 3;
                 break;
         }
 
@@ -1187,7 +1186,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
             } else {
                 goto oscillator_off;
             }
-        } else if (channels->statusFlags & SOUND_CHANNEL_SF_IEC) {
+        } else if (channels->statusFlags & SOUND_CHANNEL_SF_IEC || !((REG_NR52 >> *sp1C) & 1)) {
             channels->echoLength--;
             if ((s8)(channels->echoLength & mask) <= 0) {
             oscillator_off:
@@ -1291,7 +1290,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
         if (channels->modify & CGB_CHANNEL_MO_PIT) {
             if (ch < 4 && (channels->type & TONEDATA_TYPE_FIX)) {
                 int dac_pwm_rate = REG_SOUNDBIAS_H;
-
+                asm("" ::: "r0");
                 if (dac_pwm_rate < 0x40) // if PWM rate = 32768 Hz
                     channels->frequency = (channels->frequency + 2) & 0x7fc;
                 else if (dac_pwm_rate < 0x80) // if PWM rate = 65536 Hz
@@ -1302,7 +1301,7 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
                 *nrx3ptr = channels->frequency;
             else
                 *nrx3ptr = (*nrx3ptr & 0x08) | channels->frequency;
-            channels->n4 = (channels->n4 & 0xC0) + (*((u8*)(&channels->frequency) + 1));
+            channels->n4 = (channels->n4 & 0xC0) + ((channels->frequency & 0x3F00) >> 8);
             *nrx4ptr = (s8)(channels->n4 & mask);
         }
 
@@ -1329,7 +1328,6 @@ NONMATCH("asm/non_matching/m4a/CgbSound.inc", void CgbSound(void)) {
         channels->modify = 0;
     }
 }
-END_NONMATCH
 
 void m4aMPlayTempoControl(MusicPlayerInfo* mplayInfo, u16 tempo) {
     if (mplayInfo->ident == ID_NUMBER) {